|It is true that a short resume is generally more effective than a long resume, but it is also possible to make a resume so short that the screener says, "So long." It sounds like you have gone from terse to sparse, and that will not serve you well.|
Your resume is a sales tool that should build the screener's desire to know more about you. When you only provide job titles and dates, you are leaving out compelling information that could build interest in you, such as your responsibilities, achievements, and successes.
In addition, although you believe that job titles give the screener a clear picture of your responsibilities, there are many cases where jobs with the same title have very different responsibilities. And further, there are some companies in which the title of "manager" indicates high-level responsibilities, and other companies in which the title of "vice president" does not mean much at all.
By relying strictly on titles, you are omitting key words that could draw further attention to your resume. And worse, some screeners will look at your brief resume and hypothesize that you are lazy. As a result, you should indeed keep your resume short, but not to the point that you short-change yourself.